As of r701, PMS supports a new command-line option, profiles. If supplied, PMS displays a file chooser at startup which can be used to select a profile file or directory to read from and/or write to (see here for the details).

This option makes it easy to run multiple different configurations of PMS simultaneously without fiddling with environment variables. A "PS3 Media Server (Select Profile)" shortcut, similar to Firefox's Profile Manager shortcut, has been added to the Start Menu in the Windows build, and Linux packagers might want to add something similar.